JP3954273B2 - Electronic still camera tilt angle detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic still camera including an inclination sensor that detects an inclination angle of a camera body.
[0002]
[Prior art]
In a conventional electronic still camera, when an image obtained through a photographing optical system is displayed on a computer display device, an image sensor equipped with a tilt sensor is used to adjust the vertical direction of the image to the posture of the camera body. Are known. That is, the tilt sensor detects whether the camera body is set to the vertical position or the horizontal position. For example, when the camera body is set to the vertical position, the display device displays a vertically long image. In addition, tilt data indicating the vertical position is recorded on the recording medium together with the image data.
[0003]
[Problems to be solved by the invention]
The tilt sensor is usually configured to detect the tilt of the camera body by a rolling element such as a ball. Therefore, for example, when the camera body vibrates, such as when taking a picture on a vehicle, the position of the rolling element becomes unstable, and the output signal of the tilt sensor, that is, the vertical / horizontal position information of the camera may be erroneously detected. There is.
[0004]
An object of the present invention is to provide a tilt angle detection device capable of easily avoiding erroneous detection when erroneous detection by a tilt sensor is likely to occur.
[0005]
[Means for Solving the Problems]
A tilt angle detection apparatus for an electronic still camera according to the present invention includes a tilt sensor that outputs a signal indicating a tilt angle of a camera body, a signal change detection unit that detects a change in an output signal of the tilt sensor within a predetermined time, and a signal It is characterized by comprising angle information determination means for determining angle information that is a constant value, which is determined as the actual tilt angle of the camera body based on the detection result by the change detection means.
[0006]
The angle information determination means may determine one of the output signals of the tilt sensor as angle information, or may determine an output signal with a relatively high detection frequency as angle information. The angle information determination unit may determine a default value as angle information. Furthermore, it is preferable that the angle information determination unit determines a value corresponding to the output signal immediately before a predetermined time elapses as the angle information.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a state in which an electronic still camera to which the first embodiment of the present invention is applied is viewed from the rear.
[0008]
This electronic still camera is a single-lens reflex camera, and the interchangeable lens 11 is detachably attached to the camera body 90. An optical viewfinder 91 is provided at the center of the upper portion of the camera body 90, and a liquid crystal panel (liquid crystal display element) 46 is provided at the approximate center of the back surface 92. On the liquid crystal panel 46, an image obtained by the interchangeable lens 11 that is a photographing optical system is displayed as a moving image, and a still image stored in a memory (not shown) can be displayed by a photographing operation. A mode setting switch 95 is provided beside the liquid crystal panel 46. The mode setting switch 95 is provided for setting various operation modes, and is a jog dial in the illustrated embodiment.
[0009]
When the camera body 90 is viewed from the back 92 side, a shutter button 93 and a status display device 55 are provided on the right side of the upper part of the camera body 90. The status display device 55 includes a liquid crystal display element, and various setting states of the electronic still camera are displayed on the liquid crystal display element as characters or symbols.
[0010]
A card slot 96 is formed on the side surface of the camera body 90. The card slot 96 is provided for inserting a PC card (memory card) into the camera body 90, and a card connector (not shown) into which the PC card is inserted is provided inside the card slot 96.
[0011]
A tilt sensor is provided in the camera body 90. The tilt sensor is configured such that the camera body 90 is placed in the horizontal position, i.e., as shown in FIG. 1 or in an inverted state, or the vertical position, i.e., from the state shown in FIG. It can be detected whether it is in a state of being rotated about 90 degrees around the optical axis, and a signal corresponding to these states is output. Since the configuration of the tilt sensor is conventionally known, the description thereof is omitted.
[0012]
FIG. 2 is a block diagram mainly showing an electrical configuration of the electronic still camera.
The interchangeable lens 11 is electrically connected to an electric circuit provided in the camera body 90 (FIG. 1) via mount pins 12 and 13. A front lens group 14 and a rear lens group 15 are provided in the lens barrel of the interchangeable lens 11, and a diaphragm 16 is disposed between these lenses 14 and 15. The lenses 14 and 15 are displaced in the direction of the optical axis under the control of the lens control circuit 17 to perform focus adjustment. The lens control circuit 17 operates in accordance with a control signal sent from the system controller 31 provided in the camera body via the mount pin 12. The aperture 16 operates in accordance with a control signal sent from the aperture drive circuit 32 provided in the camera body via the mount pin 13, and the opening of the aperture 16 is adjusted. The aperture drive circuit 32 is controlled by the system controller 31.
[0013]
A half mirror 21 is provided on the optical axis of the lenses 14 and 15 in the camera body. The half mirror 21 is fixed at a position inclined by about 45 degrees with respect to the optical axes of the lenses 14 and 15. A focus plate 22 is provided above the half mirror 21, and a pentaprism 23 is provided above the focus plate 22. A finder eyepiece 24 is disposed behind the pentaprism 23. Therefore, the light taken in from the lenses 14 and 15 is reflected by the half mirror 21 and guided to the pentaprism 23 side, and the subject image is observed through the eyepiece lens 24.
[0014]
An infrared cut filter 26 and an optical low-pass filter 27 are provided behind the half mirror 21. A CCD (imaging device) 33 is provided behind the optical low-pass filter 27. Therefore, the light taken in from the lenses 14 and 15 passes through the half mirror 21 and is irradiated on the light receiving surface of the CCD 33. That is, an image obtained by the lenses 14 and 15 is formed on the light receiving surface, and the CCD 33 generates an imaging signal corresponding to the image.
[0015]
A pulse signal generation circuit (PPG) 36 is connected to the system controller 31, and the pulse signal generation circuit 36 generates various pulse signals under the control of the system controller 31. Based on these pulse signals, the CCD drive circuit 37, the A / D converter 38, and the image signal processing circuit 39 are driven, and the CCD drive circuit 37 controls the operation of the CCD 33. That is, the image pickup signal read from the CCD 33 is converted into a digital signal by the A / D converter 38 and subjected to predetermined image processing in the image signal processing circuit 39. The image signal processing circuit 39 is connected to a memory (buffer memory) 40 having a sufficient capacity for storing digital image data corresponding to one image.
[0016]
A monitor interface 41 and a card interface 42 are connected to the image signal processing circuit 39. These interfaces 41 and 42 are controlled by the system controller 31.
[0017]
A backlight 45 and a liquid crystal panel 46 are connected to the monitor interface 41 via a liquid crystal drive circuit 44. In the liquid crystal panel 46, as described above, the liquid crystal driving circuit 44 is controlled based on the image pickup signal read from the CCD 33, whereby the image obtained by the interchangeable lens 11 is displayed as a moving image, and the memory 40 The liquid crystal driving circuit 44 is controlled based on the image data read out from, and a still image is displayed. A card connector 47 is connected to the card interface 42, and a PC card 43 can be attached to the card connector 47.
[0018]
An AF sensor 51 and a photometric sensor 52 are connected to the system controller 31. The AF sensor 51 has a conventionally known configuration, and the AF sensor 51 measures the focus adjustment state of the lenses 14 and 15. The photometric sensor 52 performs photometry to determine the opening of the diaphragm 16 at the time of exposure and the charge accumulation time (exposure time) in the CCD 33.
[0019]
The system controller 31 is connected to a photometric switch 53, a release switch 54, and a status display device 55. The metering switch 53 is turned on by half-pressing the shutter button 93, whereby the metering sensor 52 performs metering. The release switch 54 is turned on by fully pressing the shutter button 93, whereby the image pickup operation of the CCD 33 is started, and an image pickup signal corresponding to the image is generated in the CCD 33.
[0020]
Further, a mode setting switch 95 is connected to the system controller 31. As described above, the mode setting switch 95 is a jog dial. When the mode setting switch 95 is pressed at a rotational position corresponding to the operation mode, the operation mode is set. As an operation mode, for example, there is a position information detection recording mode in which it is detected whether the camera body is in the horizontal position or the vertical position and the information is recorded.
[0021]
A tilt sensor 81 is connected to the system controller 31, and the camera body 90 is set to either the horizontal position or the vertical position based on a signal output from the tilt sensor 81 and indicating the tilt angle of the camera body 90. It is determined whether or not
[0022]
FIG. 3 is a flowchart of a shooting operation control routine which is a program for performing a shooting operation. This program is executed in the system controller 31.
[0023]
In step 101, execution of the camera angle information determination routine shown in FIG. 4 is started. That is, the shooting operation control routine and the camera angle information determination routine are executed in a time-sharing manner in the system controller 31 in parallel, and while the shooting operation control routine is being executed, Angle information A, which is a rotation angle around the optical axis of the photographing optical system, is detected by a camera angle information determination routine.
[0024]
In step 102, it is determined whether or not the photometric switch 53 has been turned on. Step 102 is repeatedly executed while the photometric switch 53 is in the off state. When the photometric switch 53 is in the on state, the process proceeds to step 103 where photometry and exposure calculation are executed. That is, the opening degree of the diaphragm 16 and the shutter speed are determined. In step 104, it is determined whether or not the release switch 54 has been turned on. When the release switch 54 is in the OFF state, the process returns to step 102. When the release switch 54 is in the ON state, the process proceeds to step 105.
[0025]
In step 105, the camera angle information determination routine is temporarily stopped and the angle information A obtained in the camera angle information determination routine is referred to. In step 106, an electronic shutter operation, that is, exposure in the CCD 33 is started via the CCD drive circuit 37. In step 107, it is determined whether or not the exposure has ended, that is, whether or not the CCD 33 has been exposed for a time corresponding to the shutter speed determined in step 103. If it is confirmed in step 107 that the exposure has been completed, the process proceeds to step 108 where the image signal generated in the CCD 33 is read from the CCD 33, converted into digital image data, and stored in the memory 40.
[0026]
In step 109, rotation processing is performed on the image data read from the memory 40, and the image is rotationally displaced about its center by the angle indicated by the angle information A and displayed on the LCD 46. For example, when shooting is performed with the camera body 90 set to the vertical position, a vertically long image is displayed on the LCD 46 by the processing of step 109. In step 110, angle data and image data corresponding to the angle information A are recorded in the PC card 43, and this program ends.
[0027]
FIG. 4 is a flowchart of the camera angle information determination routine.
In step 201, the angle information A of the camera body 90 is set to a default value (= 0 °). In step 202, it is determined whether or not the vertical / horizontal position detection recording mode is set. The vertical / horizontal position detection recording mode is set by operating a mode setting switch 95. When this mode is set, angle information A is obtained based on the output signal of the tilt sensor 81, and this mode is set. Based on the angle information A, the image is rotationally displaced and displayed on the LCD 46 (step 109 in FIG. 3), and the angle data and image data corresponding to the angle information A are stored in the PC card 43. It is recorded (step 110 in FIG. 3).
[0028]
When it is determined in step 202 that the vertical / horizontal position detection recording mode is set, step 203 is executed, and an output signal from the tilt sensor 81, that is, the angle A0 of the camera body 90 is detected. The tilt sensor 81 is configured to output a signal corresponding to any of 0 °, 90 °, 180 °, and −90 ° according to the rotational position of the camera body 90 around the photographing optical axis. In step 204, the timer is set to a predetermined time, and in step 205, the timer is started.
[0029]
In step 206, it is determined whether or not a predetermined time (for example, 10 seconds) has elapsed since the start of the timer. When the predetermined time has not yet elapsed, the angle A1 of the camera body 90 is detected by the tilt sensor 81 in step 207. In Step 208, it is detected whether or not the angle A0 that is the initial value obtained in Step 203 is equal to the angle A1 that is the comparison value detected in Step 207. When the angles A0 and A1 are equal, step 206 is executed again. That is, steps 206 to 208 are repeatedly executed while the output signal of the tilt sensor 81 is not changed.
[0030]
In execution of steps 206 to 208, if the output signal of the tilt sensor 81 changes before the predetermined time elapses, the process proceeds from step 208 to step 209, and the default value determined in step 201 is stored in the angle information A of the camera body 90. (= 0 °) is replaced. Then, the process returns to step 202. Next, when step 203 is executed, the inclination sensor 81 detects the angle A0 again, and steps 204, 205, and 206 are executed in this order. If the output signal of the tilt sensor 81 changes again while the loops of steps 206 to 208 are being executed, the process proceeds to step 209 and the above-described operation is repeated.
[0031]
When a predetermined time elapses while the loops of steps 206 to 208 are being executed, the process proceeds from step 206 to step 210, and the angle A0 detected in step 203 is adopted as the angle information A of the camera body 90. . Then, returning to step 202, after steps 202 to 205 are executed, the loop of steps 206 to 208 is executed again.
[0032]
On the other hand, if it is determined in step 202 that the vertical / horizontal position detection recording mode is not set, steps 203 to 208 are skipped and step 209 is executed. Therefore, a default value (= 0 °) is adopted as the tilt angle of the camera body 90.
[0033]
As described above, in this embodiment, when it is detected in step 203 that the output signal of the tilt sensor 81 has changed before the predetermined time has elapsed after the angle A0 is detected by the tilt sensor 81, step 202 is performed. Returning to step 203, the angle A0 is detected again by the tilt sensor 81 in step 203, and when a predetermined time has elapsed, in step 210, the angle A0 detected in step 203 is a constant value indicating the actual tilt angle of the camera body 90. It is determined as certain angle information A. That is, when the position of a rolling element such as a ball provided in the tilt sensor 81 is unstable because the camera body 90 is vibrating, one of the angles A0 and A1 is A0. Thus, erroneous detection of the vertical / horizontal position information of the camera body 90 can be avoided.
[0034]
FIG. 5 is a flowchart of the camera angle information determination routine in the second embodiment. This camera angle information determination routine is interrupted, for example, every 10 msec, and step 101 (see FIG. 3) is not provided in the shooting operation control routine of the second embodiment. Other configurations are the same as those of the first embodiment.
[0035]
The processing contents of each step in the camera angle information determination routine of FIG. 5 are the same as the corresponding steps shown in FIG. In FIG. 5, the reference numerals assigned to the respective steps are indicated by adding “100” to the reference numerals of the corresponding steps in FIG.
[0036]
According to the second embodiment, when the output signal of the tilt sensor 81 changes before the predetermined time has elapsed from the detection of the angle A0 by the tilt sensor 81, the camera body 90 is placed in a horizontal state in step 309. Is adopted as the actual inclination angle (default value). When the predetermined time has elapsed, in step 310, the angle A 0 detected in step 303 immediately before is used as the angle information A of the camera body 90.
[0037]
That is, in this embodiment, when the output signal of the tilt sensor 81 is unstable, the default value is adopted. The horizontal state is a state in which the camera body 90 is most likely to be placed. Therefore, when the output signal of the tilt sensor 81 is unstable, the tilt angle may be regarded as 0 °. In this way, erroneous detection of the vertical / horizontal position information of the camera body 90 can be avoided.
[0038]
6 and 7 are flowcharts of the camera angle information determination routine in the third embodiment. In this embodiment, the shooting operation control routine and the camera angle information determination routine are executed in parallel as in the first embodiment, while the shooting operation control routine is being executed. The angle information A of the main body 90 is detected by the camera angle information determination routine.
[0039]
In step 401, the angle information A of the camera body 90 is set to a default value (= 0 °). If it is detected in step 402 that the vertical / horizontal position detection recording mode is set, the process proceeds from step 402 to step 403, where the counters N0, N1, N2, and N3 are cleared to zero. In step 404, the timer is set to a predetermined time, and in step 405, the timer is started.
[0040]
In step 406, the tilt sensor 81 detects the angle A0 [0 ° / 90 ° / 180 ° / −90 °] of the camera body 90. When it is determined in step 407 that A0 = 0 °, 1 is added to the counter N0 of 0 ° in step 408. When A0 ≠ 0 °, step 409 is executed. When it is determined in step 409 that A0 = 90 °, 1 is added to the counter N1 of 90 ° in step 410. When A0 ≠ 90 °, step 411 is executed. When it is determined in step 411 that A0 = 180 °, 1 is added to the counter N2 of 180 ° in step 412. When A0 ≠ 180 °, that is, when A0 = −90 °, step 413 is executed, and 1 is added to the counter N3 of −90 °.
[0041]
After the processing of Steps 408, 410, 412, and 413, Step 414 is executed. In Step 405, it is determined whether or not a predetermined time has elapsed since the timer was started. Before the predetermined time elapses, the process returns to step 406. When the predetermined time elapses, the process proceeds to step 421. In this way, by executing the loop of steps 406 to 414, the detection frequency of the output signals at the respective angles of 0 °, 90 °, 180 °, and −90 ° within a predetermined time is changed to the counters N0, N1, N2, Accumulated as N3.
[0042]
In step 421, it is determined whether or not the counters N0 ≧ N1, N0 ≧ N2, and N0 ≧ N3, that is, whether or not the value of the counter N0 is maximum. When the value of the counter N0 is the maximum, step 422 is executed, and 0 ° is adopted as the angle information A of the camera body 90. When the value of the counter N0 is not the maximum, step 423 is executed to determine whether N1> N0, N1 ≧ N2, and N1 ≧ N3, that is, whether the value of the counter N1 is maximum. When the value of the counter N1 is the maximum, step 424 is executed, and 90 ° is adopted as the angle information A. When the value of the counter N1 is not the maximum, step 425 is executed to determine whether N2> N0, N2> N1, and N2 ≧ N3, that is, whether the value of the counter N2 is maximum. When the value of the counter N2 is the maximum, step 426 is executed and 180 ° is adopted as the angle information A. When the value of the counter N2 is not the maximum, that is, when the value of the counter N3 is the maximum, step 427 is executed and −90 ° is adopted as the angle information A.
[0043]
After steps 422, 424, 426, and 427, the process returns to step 402 and the above-described operation is repeated.
[0044]
As described above, in the present embodiment, an output signal having a relatively high detection frequency in the tilt sensor 81 is determined as the angle information A. Therefore, even if the output signal of the tilt sensor 81 is unstable, angle information with a high probability is selected, so that erroneous detection of the vertical and horizontal position information of the camera body 90 can be avoided.
[0045]
【The invention's effect】
As described above, according to the present invention, when erroneous detection by the tilt sensor is likely to occur, the erroneous detection can be easily avoided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a state in which an electronic still camera to which a first embodiment of the present invention is applied is viewed from behind.
FIG. 2 is a block diagram mainly showing an electrical configuration of an electronic still camera.
FIG. 3 is a flowchart of a photographing operation control routine.
FIG. 4 is a flowchart of a camera angle information determination routine according to the first embodiment.
FIG. 5 is a flowchart of a camera angle information determination routine in the second embodiment.
FIG. 6 is a flowchart of a camera angle information determination routine according to the third embodiment.
FIG. 7 is a flowchart of a camera angle information determination routine according to the third embodiment.
[Explanation of symbols]
81 Tilt sensor 90 Camera body

Claims (3)

Based on a tilt sensor that outputs a signal indicating the tilt angle of the camera body, a signal change detecting means that detects a change in the output signal of the tilt sensor within a predetermined time, and a detection result by the signal change detecting means, the camera Angle information determination means for determining angle information that is a constant value, which is determined as an actual inclination angle of the main body, and timer means for measuring the predetermined time, wherein the timer means is the output signal within the predetermined time. Is detected, the angle information determination means starts a new measurement for the predetermined time in order to obtain the angle information, and the angle information determination means detects no change within the predetermined time. A tilt angle detection device for an electronic still camera, wherein the output signal is determined as the angle information .   2. The tilt angle detection apparatus according to claim 1, wherein when the signal change detection unit detects a change in the output signal, the angle information determination unit determines a default value as the angle information. When the predetermined time has elapsed without the signal change detecting means detecting a change in the output signal, the angle information determining means uses a value corresponding to the output signal immediately before the predetermined time has passed as the angle information. The tilt angle detection apparatus according to claim 2 , wherein the tilt angle detection apparatus determines the tilt angle.

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